Rotary positive displacement machine



' Filed Sept. 26. 1960 Oct. 1967 w J. I. M. ARTAJO 3,349,757 v ROTARY POSITIVE DISPLACEMENT MACHINE s Shets-Sheet 1' mmvrong 40s: mac/o me mv 42114.10

ATTOEN 5.

Oct. 31, 1967 J. 1. M. ARTAJO 3,349,757

ROTARY POSiTIVHDISPLACEMENT MACHINE Filed Sept. 26, 1960 3 Sheets-Sheet 5 134a QZl JOSEIGMCIO MAQTIWAPTAJO 8 BY v 477QNYS v IN VEN TOR.

United States Patent 3,349,757 ROTARY POSITIVE DISPLACEMENT MACHINE Jos Ignacio Martin Artajo, Madrid, Spain, assignor to Research Corporation, New York, N.Y., a corporation of New York Filed Sept. 26, 1960, Ser. No. 58,564

Claims priority, application Spain, Feb. 27, 1960, 256,112;

May 20, 1960, 258,266 9 Claims. (Cl. 123-47 (1) Multiple individual rotating pistons In this class of machine the individual piston elements rotate on separate shafts which are synchronized through a gearing mechanism to insure proper phasing. Examples are found in US. Patents Nos. 2,097,881, 2,164,462 and 2,794,429.

(2) Multiple integral rotating pistons This class of machine is found to be divided into subclasses as follows:

(a) Eccentrically mounted rotors within a rotating outer chamber as illustrated in US. Patents Nos. 1,968,- 113 and 2,740,386.

(b) Eccentrically mounted rotors within a stationary outer chamber as described in articles on the Kreiskol- 'benmaschine in the magazine Verein Deutscher Ingenieure Zeitschrift, vol. 102, No. 8, Mar. 11, 1960, published at Dusseldorf, Germany.

(c) Concentrically mounted rotors rotating within a circular chamber and having synchronized valve members projecting through the walls of the outer chamber as illustrated in US. Patents Nos. 2,275,205, 2,655,112, 2,722,201, 2,863,425 and 2,927,560.

The machine of the present invention is in a further subdivision of the second class in that it comprises a single concentric rotor and interconnected articulated piston members linked thereto, rotating within a fixed tortuous chamber and requiring no internal valve members. The machine will function either as in internal combustion engine or a compression pump when driven from an external prime mover. As an internal combustion engine it is readily adapted to function either as a sparkignition engine (Otto cycle) or as a compression-ignition engine (diesel cycle). As a spark-ignition engine it may be designed to function with carburetors, gas-mixing valves or fuel-injection systems.

Any of the various well-known modes of thermodynamic operation of internal combustion machines and the various fuel input systems may be used with my machine and only tend to affect the placement of intake ports, exhaust ports and ignition points. A typical system will be described merely for illustrative purposes.

Basically, the present invention comprises an outer block member having symmetrical inner chamber developed from a polygon having an even number of sides such as as square, hexagon, octagon, etc. The polygon selected need not be limited to a regular polygon. Alternate interior surface sectors are then cut away to form concave surfaces of one curvature. The intermediate interior surface sections are cut to form second con- ICC cave surfaces having a different curvature. At their points of juncture the adjacent arcs have a common tangent. Shoe-like piston members are provided each having an outer convex surface of substantially the same form or curvature as the least concave sectors of the outer chamber. The opposite or inner surface of each piston member has gear teeth or a rack cut therein and meshing with a common gear wheel fixed upon a shaft disposed for rotation at the center of the polygon. With this construction, the individual piston members are maintained in a periodic phase with respect to each other due to the gearing arrangement. Individual pistons are free to rock slightly with respect to the gear wheel as they rotate from cavity to cavity to insure sealing contact with the outer chambers.

The internal surface of the block is thus provided with an integral number of pairs of concave sectors, each pair of sectors comprising a shallow and a deep cavity. The walls of these cavities define one boundary of a compression chamber (shallow cavity) and an expansion chamber (deep cavity). The block is enclosed by end plates which define the longitudinal boundaries of the compression and expansion chambers. The shoe-like piston has an angular dimension substantially equal to the angular stated in another manner, the angular width of the piston is approximately equal to 360 divided by the number of sectors. As the piston slides about the inner surface of the block and comes into radial alignment with the deeper of a pair of cavities a chamber of maximum volume exists between the piston, the block and the end wall members, when the piston becomes radially aligned with the shallower cavity of the pair a chamber of minimum volume exists between the piston, the block and the end wall members. As the piston revolves between these two adjacent cavities an enclosed chamber or volume is formed which varies from a designed maximum volume to the minimum volume or vice versa depending upon the location of the piston in the cycle. Thus a fluid introduced into the chamber at the point of maximum volume (piston in alignment with expansion chamber) will be increasingly compressed as the piston moves towards a position of minimum volume (piston in alignment with compression chamber).

Some of the advantages resulting from an engine of the present design are enumerated below.

The arrangement where diametrically opposed pistons are fired simultaneously causes balanced forces to be applied to the main shaft thus minimizing the bearing load requirements necessary in an unbalanced system. There is no intricate precision crankshaft required nor any counter-balancing problem as encountered in standard engines. Due to the symmetrical design, the rotor is dynamically balanced. This design lends itself to lower inertial forces, higher speeds of rotation, light weight and fewer component parts, which tend to yield high performance characteristics at a greatly reduced cost.

The new machine can be adapted for operation either as a jet-propulsion generator or a fluid pump in addition to operation as an internal combustion engine.

Preferred embodiments of the machine will now be described in detail with reference to the drawings in which:

FIG. 1 is a cross-sectional view of one form of the block member with a hexagonal chamber, illustrating the development of the inner surface;

FIG. 2 is a similar view of another form of the block member forming a chamber of octagonal design;

FIG. 3 is a view similar to FIG. 1 but also illustrating the piston arrangement;

FIG. 4 is a partial sectional view of the machine of FIG. 3, taken along line 44 of FIG. 3;

dimension of the concave sectors of the block, or, as-

FIG. 5 is a detail sectional view of the piston shown in FIG. 1, illustrating the side sealing means;

FIG. 6 is an expanded end view of the piston illustrating the end-sealing mechanism, rack gear and lower surface profile;

FIG. 7 is a schematic view of the piston in position within the block, equivalent to bottom dead center in a conventional piston engine, to illustrate calculation of the compression ratio; and

FIG. 8 is a cross-sectional view of an engine of basic octagonal shape having six piston elements and illustrating the positions of intake and exhaust ports.

I have illustrated in FIG. 1 the development of a motor block in accordance with the present invention where the block is developed from a hexagon. A motor of this characteristic has an odd number of compression and expansion cavities and would be adaptable to operate with either one or three pistons each of which would generate three power strokes per revolution. Thus a 3- piston hexagon engine would develop nine power strokes per revolution. To develop the chamber profile 2 within the block, generally indicated at 1, lay out the hexagon ABCDEF having a center 0. Lay out the chords, AB, BC, CD, DE, EF and FA, bisect alternate of said chords and locate their centers 00. Lay out the radii from each center 00 to the two points on the opposite side of the hexagon as indicated by the dotted lines, and draw the arcs FA, BC and DE having the radius of curvature 00A. At the intermediate sections establish the intersection of intersecting diagonals F00 and E00, B00 and A00, and D00 and CO0 as indicated at points 0 These points will lie on the lines OO0. Using the 0 points as centers, draw the arcs AB, CD and EF having the radius O -F.

The cavity profile now having been established, the block 1 is machined to that configuration by any wellknown means.

The development of an engine based upon an octagonal design is illustrated in FIG. 2. Within the block 1 is constructed the octagonal ABCDEFGH. As in the hexagonal case of FIG. 1 the alternate chords AB, CD, EP and GH are drawn and bisected to establish the points 00 from which the arcs AB, CD, EF and GH are drawn having a radius 00A=O0B. The alternate arcs BC, DE, PG and HA are determined as in the previous example, having their centers 0 located at the intersection of the lines 00B (00 in the EF sector) and 00C (00 in the GH sector), etc.

In each of the two arrangements discussed above in reference to FIGS. 1 and 2, a simplified method of developing the cavities was described wherein the fundamental polygons were regular the cavity profiles were arcuate sections of simple circles and the centers of these arcs were specified at various geometric points on lines passing through the center of rotation 0. Those arrangements are merely examples of one form of my invention where the centers of one set of arcs are placed at points 00, the centers of the sides of the polygon, and the centers of the alternate arcs were otherwise specified. It is to be noted that these centers were situated on lines O-Oa which are radii of the circle inscribed within the polygon and tangent thereto at the points 00. If it is desired to change the compression ratio of the machine these centers may be moved closer or further away from the center of rotation 0 so long as they remain on radial lines passing through the points 0 and 00.

The polygons need not be exactly regular polygons having equal sides but must be substantially so. It is an essential characteristic of this design that if a chord, having a length equal to the side of the polygon representing maximum compression, were moved, as by sliding or rolling around the inner surface of the chamber, the chord must, at every point in its travel, be somewhere tangent to a circle of constant radius having its center located at point 0, the geometrical center or axis of rotation of the 4 machine. I choose to define a curve having the above characteristic as a mesotrochoid.

Likewise, the cavities in the block 1 need not be confined to profiles which are arcs of geometric circles but may be defined by other mathematical formulae wherein the radii of curvature are not constant. Any of these well known mathematical curves are usable so long as they are of the character described above where a chord of constant length when slid around the chamber remains tangent to a circle of constant radius at every point in its travel.

FIG. 3 illustrates, in transverse section, the general arrangement of piston and gear components of a motor developed in accordance with the block of FIG. 1. FIG- URE 4 is a partial cross-sectional view of the assembly taken along line 44 of FIG. 3 FIG. 5 is a magnified cross-sectional view of the piston and end wall arrangement to illustrate the operation of the side sealing members 14. FIG. 6 is a partial sectional view of the piston member B illustrating the arrangement of the end sealing members 18.

As shown in FIGS. 3 and 4, the block 1 is enclosed at each end by suitable plate members 3 having central openings to receive bearings 4 which journal the shaft 5. Centrally positioned on the shaft 5 is the gear 6 locked to the shaft by key 11 and having outer teeth 7 adapted to engage the teeth 8 on the inner portion of the piston 9. The spaces between gear 6 and end walls 3 are occupied by the piston guide rings 10 having bearings 12 to permit the guide ring to float between the shaft 5 and the outer members with a minimum of friction therebetween. The underside of the piston is undercut as at 13 to permit the piston to ride on the guide rings 10 to be more fully described below.

The outer surfaces of the pistons 9 are so machined as to conform to the shape of the block cavities having the greater radius of curvature as in the sectors BC, DE and FA of FIG. 1. The piston is shown in greater detail in FIGS. 5 and 6. The grooves 17 and 19 are tmachined in the pistons to receive the compression seals or bars 14 and 18 which are biased outwardly by suitable expansion spring members 20 against the chamber surfaces 2 and 3, and function as ordinary piston rings in a reciprocating piston engine to maintain compression with the cavity defined by the platen surface and the outer block. The side compression seals 14 are grooved at 15 for purpose of lubrication in the ordinary manner. The end compression seals 18 are tapered as shown to provide a) line contact seal with the inner surface of the cham- The undercut portions 13 on the inner surface of the pistons 9 are determined by machining the piston blocks 9 with the pistons in position within the block 1 using a cutting tool rotating about the central axis 5 and having a radius equal to that of the guide rings 10. As the machining progresses the pistons are slowly advanced in positions until all positions of rotation have been assumed. It will be noted at this point that the resulting surface 13 will assume a double curve symmetrical about the centerline of the piston. The pistons will assume a position as shown in FIG. 3 only at the points of maximum and minimum compression. At other times the pistons will cant slightly and ride on the curved portions 13 during transitions between the maximum and minimum compression points.

As illustrated in FIG. 6 the outer surfaces of the pistons 9 have machined therein a fuel cavity 21 which may be of any simple geometric shape such as cubic, rectangular or hemispherical or it may be more complex such as multilobar cavity shown. The volume of this cavity is determined in accordance with usual engineering practice to achieve the desired compression ratio and represents the volume occupied by the combustible mixture of air and fuel at maximum compression. The maximum cavity available, equivalent to a piston positioned at bottom dead center in a conventional reciprocating engine, is illustrated in FIG. 7. Vc represents the minimum or clearance volume on compression and Vd represents the maximum or displacement volume. The compression ratio of my engine may then be determined by the formula:

The compression ratio and shape of the explosive chamber in the head of the piston will be governed primarily by the type of fuel to be utilized and the mode of operation desired. These factors will also determine the location of fuel intake ports, spark plugs and exhaust ports, which are machined into the block 1.

FIG. 8 illustrates a preferred embodiment of my invention wherein the block is developed in octagonal form, having cavities of mesotrochoidal form. This design gives rise to an even number of pistons which could be operated either sequentially or paired, depending on the characteristic desired. In this form I show, in phantom, along the periphery of the block the locations of the air intake ports 23, fuel injection ports 24 or 24a, and exhaust ports 25, when the engine is to be operated as a highly efficient fuel injection motor (diesel cycle).

If this arrangement were to be operated as a spark ignition engine, the spark plugs would be located in the wall of the block at location 24, the position indicated for fuel injection under diesel cycle operation and fuel injection, in the form of vaporized combustible material, would occur at an earlier point in the cycle, namely, at location 23, the position for air intake under diesel cycle operation.

Engine cooling has not been illustrated but may be accomplished either by air or circulating liquid. Air cooling may be provided by fins constructed integrally with the block and by forcing cool air into the inner or crankcase portion. For example, air forced into the air intake ports, when the cavity i not sealed by the piston, will pass between the pistons and circulate through the crankcase portion and pass out through an unsealed exhaust .port, thus cooling the interior of the engine. Liquid cooling may be utilized by designing channels in the block portion through which water or other coolant may be forced by a circulating pump in the normal manner.

The configuration of FIG. 8 illustrates the preferred embodiment of the invention wherein an octagonal block is arranged with six rotating piston members. In this case for one revolution of the crankshaft a particular piston would undergo two complete four-stroke cycles of compression, power, exhaust and intake. Six pistons displaced at 60 angles would give rise to simultaneous firings by opposed pistons resulting in 12 power strokes per revolution whereas a standard 4 cycle 6 cylinder reciprocating piston engine would undergo only 3 power strokes per revolution of the crankshaft.

In operation, referring to FIG. 8, as each of the six pistons 9 arrive at a position beneath the intake ports 23, one such position being illustrated at the dotted position to the left of the top of the diagram, air is injected into the cavity. The air is compressed into the multilobar cavity in the head of the piston as the piston advances to the position of maximum compression indicated at the top of the drawing. At that point fuel, under high compression, is injected into the cavity, via injection ports 24 or 24a, and ignition occurs immediately. The maximum power is developed as the piston advances past top dead center driving the piston, driving gear and shaft forward. As the pistons cross the bottom dead center position, illustrated by the dotted position of the piston to the right of the top of the diagram, and advance again toward a position of maximum compression, the burnt gases are swept out of the exhaust ports by the wiping action of the pistons. Thereupon, the pistons undergo a second cycle of intake, compression, power and exhaust before arriving back at their starting positions. The six pistons will thus deliver a total of twelve lution of the shaft.

I claim:

1. In a rotating machine, the combination of a block member, a'rotor member and end wall members; said block member having a hollow interior the inner surface of which is divided into an integral number of pairs of concave sectors, one sector of each pair defining an outer boundary of a compression chamber, the other sector of the pair defining an outer boundary of an expansion chamber; said end walls closing the ends of the block and defining side boundaries for each of said compression and expansion chambers; said rotor being journaled in said end walls for rotation within said block; at least one articulated piston interconnected to the rotor, said piston having an arcuate dimension substantially equal to 360 divided by the number of concave sectors, said piston further having a convex outer surface shaped to substantially conform to the curvature of said sectors which define compression chambers, said outer convex surface of said rotating piston substantially defining the inner boundary of said compression and expansion chambers, and means for maintaining said piston outwardly against the inner surface of said block, said block and end wall members forming a housing having intake and exhaust ports therein communicating to the interior of the block, said rotor having gear teeth projecting from its outer edge, the under surface of said pistons having a gear segment adapted to engage the teeth of the rotor and the means for maintaining the pistons outwardly against the inner surface of the block are guide rings journaled on the shaft of the rotor and disposed between the rotor and the end wall members.

2. The combination as set forth in claim 1 wherein the undersurface of the pistons has a centrally disposed gear segment and the remaining portions of this surface define double concave curves adapted to engage the cylindrical surface of the guide rings as the pistons traverse the chamber.

3. In a rotating machine, the combination of a block member, a rotor member and end wall members; said block member having a hollow interior the inner surface of which is divided into an integral number of pairs of concave sectors, one sector of each pair defining an outer boundary of a compression chamber, the other sector of the pair defining an outer boundary of an expansion chamber; said end walls closing the ends of the block and defining side boundaries for each of said compression and expansion chambers; said rotor being journaled in said end walls for rotation within said block; at least one articulated piston interconnected to the rotor, said piston having an arcuate dimension substantially equal to 360 divided by the number of concave sectors, said piston further having a convex outer surface shaped to substantially conform to the curvature of said sectors which define compression chambers, said outer convex surface of said rotating piston substantially defining the inner boundary of said compression and expansion chambers, and means for maintaining said piston outwardly against the inner surface of said block, said block and end wall members forming a housing having intake and exhaust ports therein communicating to the interior of the block, said intake ports being situated near the midpoints of the concave sectors of the block which define a wall of a compression chamber, the exhaust ports being situated at a side point in the alternate concave sectors of the block disposed furthest away from said intake ports as measured along the line of rotation and the convex surfaces of the pistons having fuel retaining multilobar depressions whereby said machine may be operated as a fuel injection diesel cycle internal combustion engine.

4. A rotary machine comprising a block, a chamber in said block, the peripheral wall of the chamber comprised of an even number of concave sectors, said conpower strokes per revocave sectors being of two diiferent curvatures with each alternate concave sector of said peripheral wall sectors being successively one and then the other of said two different curvatures, a rotor member mounted for rotation Within said chamber with the axis of rotation thereof centrally spaced from said peripheral wall, a plurality of piston members, means interconnecting each of the piston members for rotation with the rotor member and for independent pivotal movement relative to said rotor member and to said block about axes parallel to the rotor axis, each piston member having an outer convex surface in contact with said peripheral wall at all times at at least two spaced points along the circumference of said peripheral wall, said outer convex surface shaped to substantially conform to the curvature of said concave sectors having a lesser degree of curvature to define individual chambers bounded by said peripheral wall and said convex surface of the piston member, said chambers varying in volume upon rotation of the rotor member, and intake and exhaust ports communicating with selected concave sectors,

5. The combination as set forth in claim 4 wherein the intake and exhaust ports are situated at the points of minimum and maximum compression respectively in order that it may function as a pump.

6. The invention described in claim 4 wherein the contour of the peripheral wall of the chamber is determined by the mathematical formula of a trochoid.

7. The invention defined in claim 4 wherein chords drawn between the intersections of adjacent concave sectors of the peripheral wall of the chamber describe a polygon having an even number of sides.

8. The combination as defined in claim 4 comprising also sealing means provided at said spaced points of contact in the form of spring biased bars two of which are disposed in grooves on the sides of each piston and two of which are disposed in grooves on the outer convex surface of each piston to cooperate with the peripheral Wall.

9. The combination defined in claim 4 wherein the intake and exhaust ports are located in alternate concave sectors of the least curvature and wherein spark plug ports are located in the other of the concave sectors whereby said engine may operate as a spark ignition Ottocycle internal combustion engine.

References Cited UNITED STATES PATENTS 1,320,182 10/1919 Smith et a1 123-17 1,605,912 11/1926 Barker 123-17 1,617,863 2/1927 Planche 123-8 1,750,502 3/1930 Baker 123-17 1,753,476 4/1930 Richer 121-61 1,849,398 3/1932 Bracco 123-17 1,909,880 5/1933 Meyer 123-17 2,162,771 6/1939 Winans 123-8 2,263,361 11/1941 Lawrence 123-17 2,343,948 3/1944 Bellazini 123-17 2,435,476 2/1948 Summers 123-17 3,008,457 11/1961 Mezzetta 123-17 3,036,560 5/1962 Geiger 123-17 FOREIGN PATENTS 156,127 11/1904 Germany.

14,547 1885 Great Britain.

MARK M. NEWMAN, Primary Examiner.

RALPH H. BRAUNER, KARL J. ALBRECHT, JO- SEPH H. BRANSON, RALPH D. BLAKESLEE,

Examiners.

R. B. WILKINSON, F. T. SADLER,

Assistant Examiners. 

1. IN A ROTATING MACHINE, THE COMBINATION OF A BLOCK MEMBER, A ROTOR MEMBER AND END WALL MEMBERS; SAID BLOCK MEMBER HAVING A HOLLOW INTERIOR THE INNER SURFACE OF WHICH IS DIVIDED INTO AN INTEGRAL NUMBER OF PAIRS OF CONCAVE SECTORS, ONE SECTOR OF EACH PAIR DEFINING AN OUTER BOUNDARY OF A COMPRESSION CHAMBER, THE OTHER SECTOR OF THE PAIR DEFINING AN OUTER BOUNDARY OF AN EXPANSION CHAMBER; SAID END WALLS CLOSING THE ENDS OF THE BLOCK AND DEFINING SIDE BOUNDARIES FOR EACH OF SAID COMPRESSION AND EXPANSION CHAMBERS; SAID ROTOR BEING JOURNALED IN SAID END WALL ROTATION WITHIN SAID BLOCK; AT LEAST ONE ARTICULATED PISTON INTERCONNECTED TO THE ROTOR, SAID PISTON HAVING AN ARCUATE DIMENSION SUBSTANTIALLY EQUAL TO 360* DIVIDED BY THE NUMBER OF CONCAVE SECTORS, SAID PISTON FURTHER HAVING A CONVEX OUTER SURFACE SHAPED TO SUBSTANTIALLY CONFORM TO THE CURVATURE OF SAID SECTORS WHICH DEFINE COMPRESSION CHAMBERS, SAID OUTER CONVEX SURFACE OF SAID ROTATING PISTON SUBSTANTIALLY DEFINING THE INNER BOUNDARY OF SAID COMPRESSION AND EXPANSION CHAMBERS, AND MEANS FOR MAINTAINING SAID PISTON OUTWARDLY AGAINST THE INNER SURFACE OF SAID BLOCK, SAID BLOCK AND END WALL MEMBERS FORMING A HOUSING HAVING INTAKE AND EXHAUST PORTS THEREIN COMMUNICATING TO THE INTERIOR OF THE BLOCK, SAID ROTOR HAVING GEAR TEETH PROJECTING FROM ITS OUTER EDGE, THE UNDER SURFACE OF SAID PISTONS HAVING A GEAR SEGMENT ADAPTED TO ENGAGE THE TEETH OF THE ROTOR AND THE MEANS FOR MAINTAINING THE PISTONS OUTWARDLY AGAINST THE INNER SURFACE OF THE BLOCK ARE GUIDE RINGS JOURNALED ON THE SHAFT OF THE ROTOR AND DISPOSED BETWEEN THE ROTOR AND THE END WALL MEMBERS. 